Biophys J. 1991 Apr;59(4):945-9.  

Aging and the complexity of cardiovascular dynamics.

Kaplan DT, Furman MI, Pincus SM, Ryan SM, Lipsitz LA, Goldberger AL.

Colin Research America, Cambridge, Massachusetts 02139.

Biomedical signals often vary in a complex and irregular manner. Analysis of
variability in such signals generally does not address directly their
complexity, and so may miss potentially useful information. We analyze the
complexity of heart rate and beat-to-beat blood pressure using two methods
motivated by nonlinear dynamics (chaos theory). A comparison of a group of
healthy elderly subjects with healthy young adults indicates that the complexity
of cardiovascular dynamics is reduced with aging. This suggests that complexity
of variability may be a useful physiological marker.

PMID: 2065195 [PubMed - indexed for MEDLINE]